1. Field of the Invention
The present invention relates to a device for spanning between vertically spaced, upper and lower surfaces and, more particularly, to a modular, telescoping ramp for spanning vertically spaced, upper and lower surfaces. The device of this invention is comprised of multiple modular units that slideable extend and retract relative to one another to provide a self supporting span that can be readily adjusted, on site, to span the vertical and horizontal distances between two remote surfaces.
2. Description of the Prior Art
Ramps are routinely used to span between vertically spaced, upper and lower surfaces, such as the ground and a relatively elevated top surface of a structure, and thereby provide ease of access to and from the upper surface. Of course, ramps allow a person to slide or move an item along an inclined surface, rather than having to hoist or lift the item between the vertically spaced surfaces. Consequently, ramps are commonly used in construction sites so that materials, machinery and the like are relatively effortlessly raised and lowered between vertically spaced surfaces. Ramps are also often used to by-pass stairs or provide wheelchair access between two vertically spaced surfaces. Moreover, ramps are becoming increasingly popular with pickup truck and van owners. In this latter respect, the ramp allows the pickup owner to load the bed of the truck with items, such as motorcycles and lawnmowers, with relative ease. Other typical uses for a ramp include providing animal (pet) access to and from a conveyance; and, in the latter instance, typically include sturdy support and traction to afford a secure footing over the length of the span.
Traditionally ramps are secured to the upper surface in a manner that prevents the ramp from disconnecting from the upper surface and falling to the lower surface. For example, the upper end of the ramp may be permanently affixed to the upper surface by mechanical fasteners. However, in many instances, the ramp must be removable so that it permit it to be stowed once access to the upper surface is no longer needed. Additionally, it is often important that the ramp be highly portable so that it may be manually maneuvered, installed and removed. Moreover, where the ramp is to be use to permit ease of access to and from the tailgate of a pickup or floor of a van, the means used to afford attachment thereto must achieve this result without alteration or damage to the surface of the vehicle.
It is the object of this invention to remedy the above as well as related deficiencies in the prior art.
More specifically, it is the principle object of this invention to provide a ramp assembly for spanning between vertically spaced, upper and lower surfaces, that is safe and sturdy, yet quickly removable and highly portable.
It is another object of this invention to provide to provide a ramp assembly that is secured in its inclined orientation without damaging or permanently altering the upper surface.
It is yet another object of this invention to provide a ramp assembly of modular construction that can be extended and retracted over a relatively long span and thereby afford sturdy and secure footing between an upper and lower surface, or a flight of stairs.
Additional objects of this invention include a method for spanning a distance between two remote surfaces.
The above and related objects are achieved by provision of a ramp assembly for spanning between a first lower surface and a second relatively elevated upper surface. This assembly is defined by a structure, which may be gravity deployed by simply tilting to allow for sliding extension of the ramp; and, thereafter secured in an inclined orientation without damaging or permanently altering the upper surface. The ramp assembly of this invention is suitable for providing a safe and secure slip resistance span between virtually any loading and unloading platform. In the context of this invention, it is understood that the term xe2x80x9cplatformxe2x80x9d is inclusive of the bed or interior of a truck or van, and any surface that is above or below the surface of the bed or interior of a truck or van. Accordingly, one such platform can be a conveyance (truck or van), or the landings at the top and the bottom of a flight of stairs.
The ramp assembly includes at least two elongated runners, preferably formed of a light weight structural plastic or aluminum, and an angular support member attached to, or integral with each end of each runner, and having a first portion thereof configured for engaging the upper surface and lower surface. Upon deployment and placement of the ramp assembly in an inclined orientation, each angular support member engages the upper and lower surfaces at an inclined angle relative to the ramp surface. The assembly can also include an additional runner disposed intermediate between each of two supporting runners that engage the upper and lower surfaces (hereinafter also xe2x80x9ctopxe2x80x9d and xe2x80x9cbottomxe2x80x9d runners, or xe2x80x9cendxe2x80x9d runners), respectively. Each of two xe2x80x9ctopxe2x80x9d and xe2x80x9cbottomxe2x80x9d runners are similarly configured, relative to said intermediate runner, to slidingly engage and support the intermediate runner, and thereby allow for cooperative reciprocal (telescoping) extension and retraction thereof.
In order to insure secure footing on the inclined surfaces of the ramp, the surface of the ramp can be textured in the course of manufacture, or a tread or carpet-like material added to improve traction.
In the preferred embodiments of the ramp assembly of this invention, the slide and channel configuration is design to minimize frictional forces upon deployment (extension) of the ramp, and yet provide positive locking of the ramp once weight is exerted upon the extended ramp surface. In another of the preferred embodiments, the slide and channel configuration is provided with an adjustable/moveable stop, to permit extension of the runners to a predetermined length, and thereby avoid the need to adjust the angle or distance between the upper and lower surface for each use.